How your brain sees words

This article was taken from the April 2013 issue of Wired magazine. Be the first to read Wired's articles in print before they're posted online, and get your hands on loads of additional content by <span class="s1">subscribing online.

This is a language map made by your brain. Neuroscientist Jack Gallant at the University of California and his student Alex Huth came up with an infographic that shows how common word categories, or "semantic information", is stored in our heads. "We took 1,705 words and tested how our brain understands them in relation to each other," says Gallant. Five volunteers were put into an fMRI machine that scanned their brains for activity while they watched movie trailers for three hours. "Whenever the volunteer saw a specific noun or verb, we recovered the location in the brain that lit up at the same time," explains Gallant. Brain activity was measured every two seconds and weighted so the researchers knew how much each category influences a brain region.

Jack Gallant/Alex Huth

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"The colours on the map show categories represented similarly in all our subjects' brains," Gallant explains. "Animals are yellow, people are green, vehicles are purple and places such as buildings are dark blue." The links between categories represent sub-categories and the size of each bubble indicates intensity -- so a big bubble means we recognise that object more clearly than one represented by a small bubble. The information shown above was then superimposed on to a structural brain map.

Gallant says that this organisation of word categories is far richer than previous fMRI studies had suggested. "This changes our understanding of how the brain interfaces between vision and language," he says. "For example, there aren't individual brain locations to process each category, as people thought."

This article was first published in the April 2013 issue of WIRED magazine